Problem: Solve for $n$ : $7 + n = -7$
Solution: Subtract $7$ from both sides: $ \begin{eqnarray} \\ 7 + n &=& -7 \\ \\ {-7} && {-7} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{7 + n} &\hphantom{=}& \hphantom{-7} \\ n &=& -7 {- 7} \\ \end{eqnarray} $ Simplify. $ n = -14$